1. Field of the Invention
This invention relates to a biometrics authentication method and system for individual authentication, utilizing biometric characteristics which are a portion of the human body, and in particular relates to a biometrics authentication method and system which verifies a plurality of registered biometric data sets against a detected biometric data set, and which is suitable for use in individual authentication.
2. Description of the Related Art
Among individual authentication techniques of recent years, biometrics authentication technology has attracted attention. There are numerous portions of the human body which can be used to differentiate the individual, such as fingerprints and toeprints, the retinas of the eyes, facial features, and blood vessels, so in such a biometrics authentication technology, biometrics characteristics of such portions of the human body are identified to perform individual authentication.
For example, comparatively large amounts of individual characteristic data are obtained from blood vessels in the fingers and palms of the hands, and from palmprints. Moreover, blood vessel (vein) patterns remain unchanged throughout life from infancy and are regarded as being completely unique, and so are well-suited to individual authentication.
In such biometrics authentication, first a portion of the biometric characteristics of the user himself is detected by a detection apparatus, and the detected biometric data is registered in the database of a server. Next, in order to perform individual authentication, a portion of the biometric characteristics of the user is detected by a detection apparatus, and the detected biometrics data is verified against the biometric data registered in the database, and individual authentication is performed based on degree of similarity.
In this method, in which biometric data for numerous users is registered in the database in advance, and biometrics data detected for a user is verified against the numerous biometric data sets in the database (called 1:n authentication), biometric data is registered without comparing biometric data to be registered with previously registered biometric data. On the other hand, within the biometric data there may be biometric data for other persons which is similar to ones own biometric data. In verifying biometric data, when the verification result exceeds a degree of similarity threshold, the person is authenticated as the individual in question; hence when verifying data against the similar biometric data of another person, there may be cases in which this other person is authenticated as the individual, and so identification of the individual becomes difficult.
In order to prevent confusion with other persons in such 1:n authentication, in biometrics authentication using facial images, a method has been proposed in which the other persons of biometric data with a high degree of similarity with the biometric data of the individual in question are registered in advance in an erroneous recognition persons list, and at the time of verification, upon identification as a person registered on this list, the threshold for verification is raised, and verification is again performed (see for example Japanese Patent Laid-open No. 2005-182184).
Further, in biometrics authentication using facial images, a method has been proposed in which a similarity is calculated at the time of registration, if there is a similar pattern, biometrics data is registered together with a similarity group number, and at the time of verification, when there is a similarity pattern number, the verification threshold is raised, and verification is performed (see for example Japanese Patent Laid-open No. 2003-141542).